Electric radiant heater



May 23, 1933. LEBAU ELECTRIC RADIANT HEATER Filed Jan. 25, 1932 .J QQ

w' VENTOR. BY

A TTORNE Y6.

Patented May 23, 1933 LOUIS LEBAU, OF PITTSBURGH, PENNSYLVANIA ELECTRIC RADIANT HEATER Applicationl led January 25, 1932.

'Ihis invention relates to improvements in electric heaters, and more particularly to electric radiant heaters of the character shown in my pending application Serial Number 435,463, liled March 13, 1980.

The present invention resides principally in a new `and improved baclr wall or heat-1e flector block or plate for use in such a heater, in combination with a flat electrical resistor element and an open-work radiant member,

whereby a circulation of air is provided to increase the e'liiciency of said heater.

The invention contemplates a construction embodying a heat-relector plate or block formed of suitable material and having spaced-apart receiving means for the flat resistor element to form air passages therebe* hind, said passages being in open communication with the rear of the reflector plate by means ofa series of ducts or openings. This construct-ion will provide a continuous for- `ward circulation of air through the heater.

Additional features and advantages of my invention will become apparent from the following description talen in connection with the accompanying drawing, wherein:

' Fig-1 is a front broken perspective view of a heater embodying my invention, having portions thereof removed to disclose details;

Fig. 2, a central horizontal section;

Fig. 3, a rear perspective view, particularly showing the radiant member and the resistor element therein; and y Fig. l, a front elevational view of the heatreflector plate or block.

y Referring to the drawing, 2 designates a back wall or heat-reiiector plate or block made of suitable material that may be utilized both for insulating and heat reflecting purposes. I prefer to use a plate or block formed of fire-clay, having incorporated therein saw-dust or the like which, upon firing, re-

sults in a more` or less porous body.

Such a back wall or plate, when made of substantial thickness, will sufficiently insulate the heater against any dangerous and undesirable transfer of heat from the resister element to the rear of the heater, thus preventing tire and loss of heat.

By experiments and tests, I have discov- Serial No. 588,518.

ered that when a surface of a plate or block of the character specilied is subjected to extreme heat, such as is generated by the resistor' element employed by me, it will attain a high temperature and glow with a red color. rlhe heat thus applied penetrates the material of the plate but a slight distance, being prevented from passing through thel plate by its inherent insulating properties. rI`he hot surface area of the plate acts as a refiector to reflect and radiate additional heat outwardly therefrom, thereby providing a highly eilicient back wall construction.

As illustrated, the reflector plate 2 comprises a body of rectangular shape having the .35 front or heat-reflecting face thereof formed with a rect-angular depression or recess 3. Positioned in the depression or recess, I provide a plurality of spaced-apart parallel vertically extending ribs or projecting elementsA 4L, preferably formed integral with the body.

Elements t, as shown and as preferred, are

narrow in width and are arranged in groups of three, each group consisting of outer ribs a and a central rib b, and are spaced to pro- '75 duce vertically extending air passages 5. The groups are also spaced apart to provide intervening' vertical spaces or grooves 6 for a purpose hereinafter described. A series of air ducts or openings 7 are also provided, and'80 extend rearwardly through the plate 2 from the communicating air passages 5.

In connection with such a back wall or relector plate, I prefer to employ a flat resistor element formed of thin metal strips 8 having 35 narrow spaced apart slots 9 cut therein alternately from the edges of said strips to provide a sinuous path for the current. The said strips 8 are of substantially the same width as the distance between the outer ribs a of each group hereinbefore described, and are positioned thereon.

Vhen the resistor strips 8 are thus positioned on the ribs 4, one strip for each group of three ribs, adjacent strips are electrically connect 95 ed by portions 10, either at the upper or 10W- er portions of the ribs. For this purpose, the end portions of the outer ribs a of adjacent groups are cut away, as at l1, to accommodate the connecting portions 10. The central ribs b of each group serve to support the thin flat resistor elements and prevent buckling or distortion.

Superimposed upon the block or reflector 5 plate 2 is an openwork radiant member 12; this radiant member is formed of refractory clay dthelilie includes irregular connectig face portions 14 separated by openings 15 worked into an attractive design. The radiant member substantially conformsA in shape and size tothe depression of the plate 2, and has a rearwardly extending marginal flange 16 for entrance in the outer portion of said depressidh Y iRmfliarrt member x 12 is provided with "iced-'apart verticallyA extending ribs 17 f aptedto be positioned in the spaces or ,roves between" adjacent roups of reforar 'p1aa,rib-s 4, as par-ae myshown by V' 1 2. Said ibsv 17 are cut away at their potions,.as`t"17q, to spanthe connectmg" 1 aos ledfjthe reigswfseips.

T e face of the. radi'ant'member 12 .esrcoilitacts withl theI resistir or strips @fp mainta'r'n t same at againsttheir suppmigg ribs 4, A he rib l17` @a vertaal portin the marginalflange 16 cooperate with ,grooves 6 and the de ression 3 to prevent #Q0 aterajl movement or lisengagement of the 8 l i i l, Suitable meansO my be emplyed forsecuring the radiant member 12 to the block or Apll'lte 2 For example, I Show an open "aframef mezbferQlS secured tij-said plate by @uns bf 'belts orvscrews, 19. In operation, the terminals of the resistor element'ra're connected withasource of electcal energy in 'any suitable manner. When "tr'ln'elec'trical current isapplied, the element fbcoresheawd-nd imparts heat tb the sur- Mdx medium andthe bac'k wall or reileterfllatel, as described. Due tothe bpe slbts 9 in thel resistor strips "ftheir'assagbs 5 and rearwardly extend- 'irri ductsM r 'openings 7"fin the reflector plate, a circulatinf iris induced bythe heat n'lfftlhie e'l'eieitthiotrgh'sid dhctsand pasetg'estb the element, where it is heated 'and can ef 'heater thmughthe 'opensie er meridiani; 12. r g 'lil'ls'uit'able 'casing or housing A'may be etlfor'th're'heatefes, fr example, a metal "'havi'ngan air space 21 in th'e rear "ts-*ehe e 'me haar 2e ef'the easing is pref- Iy leiaiedwith a'sr'ies'ofepeuings 23 r forsupply'gwair tothe ducts or openings 7 me reas piace. fnemreremiiy geen am, ty'meaastf w my feenstreezeatm transferer heat a the serieuses@ alarma bycdveain 'afgem- 'diie tot aircfre'tsnduced fue tjeseter through the 'reate. 'M' so," l? sl'lind eplfae Wil'adiate heat'vry mcnury.

prevista with a p situee mme fesistofelemht-e alegran I have found that by means of my heater,

a great saving in the cost of operation is effected by the construction shown, due to the fact that the full current need only be turned on while the reflector plate is heating, and 70 when it attains its glowing red color, the current'may be reduced a d the heating continued eflectively at a m erate cost.

I claim:

1,. A electric. rad'ant heater including a 76 baci( lle'c'tr plate xving an air passage formedaenaa Aface thereof and a communicating opening extending through the plate, a flatslotted electric resistor element positioned on the plate over the air passage, and an 00 openlwrk refractory radiant member superimposed on'the latein conta/ct with and over the restoele ent.

2. An electric radiant heater including a back reflector plate having air assagesrthere- 585 in and a series of air cpen ugs vextending therethrough in cdmnuhieation 'with the air pdssagesfa flat slotted 'electric resistor ele ment extending over said air passages, and "an open-Work refractory radiant member supet.0 mpesed en the plate 'and ever the resister element. v

3. An electric 'radiant theater including a back Nrefleto'r plate of insulating material luralify 'f ribs spaced* apart te provide arr 'passages therebetween, and ae'r'esv f'ir epeningsextending'theeth'lighin inilnlcntil With'tlle'ai 'B- .sa ,anat slotted electric resister-ele eat 'di posed oh the ribsbvrtlie said air liksage's, ahdaaopen-work Ffa t meneer uperiaeosd en the plate adfea gagesmr resister eleiaet. A f4. relctic vllda't'heater'ittllldlg task me; parte; sesame' -raawrruw formed "with n parcfrjsiart tob previa@ 'an arr passage' me" tween, said parte hrgan'aireecfmeaereulereoa. muniaefeswahtheairfpasege,n est eetricgesaer dem?? eaaaeieg Isae/n90 S' i in" Efiler sa 'lili-7 S" an eisawikeracelory reeaianlir'um im ose on te ate an e" 'ghga sstor'li'et p ngt f s masa 'wahl a feats ef gates Brambilla group comprising a plurality of ribs spaced apart to form air passages therebetween, said plate having grooves between said groups of ribs and air ducts extending through the plate in communication with the air passages, a flat electric resistor element comprising a series of connected slotted strips positioned with one strip over the air passages of each group of ribs, and an openswork re- 'ractory radiant member superimposed on the plate and engaging the resistor element, said radiant member having ribs entered in the grooves of the plate.

7. In an electric heater, a back-plate having a front heat reflecting surface formed with spaced-apart projections having resistor contacting free ends and forming air passages therebetween, openings extending through the plate and communicating with said passages, a flat slotted resistor element bridging the space between adjacent projections and supported by the contacting free ends thereof, and means for retaining the resistor element in position on the free ends.

8. In an electric heater, a back plate, spaced apart projection elements on a face thereof forming air passages therebetween,

vopenings extending through the back plate and communicating with the passages, a relatively flat resistor element bridging the space between adjacent projection elements and held on and supported by the projection elements.

In testimony whereof I aHiX my signature.

LOUIS LEBAU. 

